Sensors for monitoring states of doors and windows are conventional. Generally, these conventional sensors are realized in two parts. A first part of the sensor is made up of a permanent magnet. A second part of the sensor has a magnetic sensor, for example a reed contact, that can be opened or closed by the permanent magnet in the first part of the sensor. Here, a part of the sensor has to be attached to the movable frame of the window or door that is to be monitored, and the other part of the sensor has to be fastened outside the movable frame, for example on the wall. If the door or window is closed, then the reed contact is triggered by the magnetic field of the permanent magnet. If the door or the window is open, the reed contact is not triggered.
German Patent Application No. DE 103 35 126 A1 describes a device for state monitoring of an object in which a reed contact can be triggered by a permanent magnet. The device also has a transmit unit by which the ascertained state of the object, or a state change, can be communicated.
There is therefore a need for a device, realized having one part, for monitoring the state of an object.